1. Field of the Invention
The invention relates to a cooling apparatus for an engine and, more particularly, to an engine cooling apparatus designed so as to improve the efficiency in replacing a cooling liquid of an engine cooling circuit that includes a heat storage tank.
2. Description of the Related Art
Japanese Patent Application Laid-Open Publication No. 2002-188442 and No. 2000-73764 disclose engine cooling apparatuses in which a cooling circuit is provided with a heat storage tank for storing cooling liquid from an engine in a temperature maintaining fashion. The heat storage tank has a tank body and a housing. The housing has an inlet passageway for allowing cooling liquid to flow into the tank body and an outlet passageway for allowing cooling liquid to flow out from the tank body. An in-pipe passageway of a pipe inserted into the tank body is connected to the outlet passageway.
In order to maintain the engine cooling performance, it is necessary to periodically replace the cooling liquid. At the time of coolant replacement, a greater amount of cooling liquid needs to be drained if a heat storage tank is provided in the cooling circuit than if such a tank is not provided. Therefore, the provision of a heat storage tank can adversely affect the workability in replacing the cooling liquid, and can cause a prolonged replacement operation time.
Accordingly, it is an object of the invention to provide a cooling apparatus for an engine which incorporates a heat storage tank provided in a cooling circuit and which is designed to improve the efficiency in coolant replacement.